Field of the Invention
The invention relates to an electrolysis apparatus with a number of membrane electrolysis cells, each of which comprises a membrane that is provided on both sides with a contact layer.
In an electrolysis apparatus, a medium is electrolytically decomposed by applying a supply voltage between an anode and a cathode. If water is used as the medium, hydrogen and oxygen are thereby formed. Such an electrolysis apparatus can consequently be used for generating hydrogen and/or oxygen as and when required. For example, an electrolysis apparatus may be provided for injecting hydrogen as and when required into the primary coolant loop of a pressurized water reactor.
An electrolysis apparatus may be designed as a membrane electrolyzer. In that case, the electrolysis apparatus comprises a number of membrane electrolysis cells, in which the functional principle of a fuel cell is reversed. The functional principle of a fuel cell is described, for example, in the paper "Brennstoffzellen fur Elektrotraktion" [fuel cells for electro-traction], K. Strasser, VDI-Berichte [Reports by the Association of German Engineers], No. 912 (1992), pages 125 et seq.
In the case of such a membrane electrolysis cell, the water provided as the medium is supplied to a membrane arranged between the anode and the cathode, in particular a cation exchanger membrane, provided as the electrolyte. The membrane is thereby usually provided with a contact layer on each of both sides. The first contact layer serves as the anode and the second contact layer serves as the cathode. Such a membrane electrolysis cell is distinguished by a particularly compact design, so that an electrolysis unit with a number of membrane electrolysis cells can be accommodated in a particularly confined space.
For the use of an electrolysis apparatus as a hydrogen generator in the industrial sector or in the power plant sector, it is necessary for its production capacity to be designed to meet the basic hydrogen requirement. If that is the case, the design of the electrolysis apparatus as a membrane electrolyzer, which is desirable with regard to structural advantages, may be unsuitable, particularly for applications with a comparatively high hydrogen requirement.